1. Field of the Invention
The present invention pertains to an insert to be used in cutting tools for chip-forming machining operations. More particularly, the present invention relates to a multiple purpose, indexable, cutting insert having a leading cutting edge and a trailing wiper edge for semi-finishing and finishing in face, chamfer, periphery, and pocket milling applications.
2. Description of the Related Art
Indexable cutting inserts are available in various shapes. One of the most common inserts is square and includes four cutting edges. Such an insert is especially useful in cases where it is necessary to mill a square or 90-degree shoulder in the workpiece being cut.
Octagonal inserts with eight cutting edges are also widely used. Adjacent cutting edges of such an insert extend at a 45-degree angle (commonly called a lead angle) relative to one another. Octagonal inserts are particularly advantageous in that a single insert possesses a relatively large number of alternately usable cutting edges.
However, the cutting edges of the conventional octagonal insert, for example, may produce a relatively rough surface on the workpiece as the result of the milling operation. Thus, it may be necessary to subject the workpiece to a second milling operation to produce a smoother surface as desired by the customer.
The inventor of the present invention has recognized that the requirement of a second milling operation increases the costs associated with the milling operation and decreases productivity.
To solve these and other problems, an object of the invention is to provide an indexable cutting insert for use in a cutting tool having a leading cutting edge for coarse cutting operations and a trailing wiper edge for fine cutting operations.
It is another object of the invention to provide an indexable cutting insert having a rake surface and deflecting surface for effective chip control.
In one aspect of the invention, an indexable cutting insert comprises a polygonal body of wear resistant material. The body includes a center, top and bottom surfaces, and a plurality of side surfaces between the top and bottom surfaces. A plurality of leading cutting edges is formed at an intersection of the plurality of side surfaces and the top surface. Similarly, a plurality of wiper edges is formed at the intersection of the plurality of side surfaces and the top surface. A corner separates each leading cutting edge and each wiper edge. For a cutting operation, the insert engages a workpiece using one of the leading cutting edges for coarse cutting operations and one of the wiper edges for fine cutting operations.
In another aspect of the invention, an assembly of a toolholder and an indexable cutting insert being mounted within a seat in the toolholder. The cutting insert comprises a polygonal body of wear resistant material. The body includes a center, top and bottom surfaces, and a plurality of side surfaces between the top and bottom surfaces. A plurality of leading cutting edges is formed at an intersection of the plurality of side surfaces and the top surface. Similarly, a plurality of wiper edges is formed at the intersection of the plurality of side surfaces and the top surface. A corner separates each leading cutting edge and each wiper edge. For a cutting operation, the insert engages a workpiece using one of the leading cutting edges for coarse cutting operations and one of the wiper edges for fine cutting operations.